SDL+OpenGL doublebuffered... but still ripples?

I apologize if this has been answered before, but I assure you I've searched google, this forum, and gamedev.net and found nothing.

I've been working with SDL, OpenGL, and C++ on a 2D game, and I recently added the blitting of the background image. I have doublebuffering on, and if I turn it off the usual tearing and flickering occurs. But even with doublebuffering, there is a clear ripple running from bottom to top on the screen as I move the camera.

I realize this probably has something to do with vsync, but I'm not sure to fix it - does anyone have any suggestions? If you want to see the code, check http://sourceforge.net/cvs/?group_id=174909 for details on accessing the CVS.

Heh... I feel a bit silly - I actually saw the thread about how to enable vsync on Mac, but it didn't work for me because I was including "SDL_OpenGL.h" but not <OpenGL/OpenGL.h> on Apple hardware, so it couldn't find the method.